Vacuum Insulated Panel with Low Temperature Seal Having Low Carbon Content

Certain example embodiments are generally related to vacuum insulated devices such as vacuum insulating panels that may be used for windows or the like, and/or methods of making same.

Vacuum insulated panels are known in the art. For example, and without limitation, vacuum insulating panels are disclosed in U.S. Pat. Nos. 5,124,185, 5,657,607, 5,664,395, 7,045,181, 7,115,308, 8,821,999, 10,153,389, and 11,124,450, the disclosures of which are all hereby incorporated herein by reference in their entireties.

As discussed and/or shown in one or more of the above patent documents, a vacuum insulating panel typically includes an outboard substrate, an inboard substrate, a hermetic edge seal, a sorption getter, a pump-out port, and spacers (e.g., pillars) sandwiched between at least the two substrates. The gap between the substrates may be at a pressure less than atmospheric pressure to provide insulating properties. Providing a vacuum in the space between the substrates reduces conduction and convection heat transport, and thus provides insulating properties. For example, a vacuum insulating panel provides thermal insulation resistance by reducing convective energy between the two substrates, reducing conductive energy between the two transparent substrates, and reducing radiative energy with a low-emissivity (low-E) coating provided on one of the substrates. Vacuum insulating panels may be used in window applications (e.g., for commercial and/or residential windows), and/or for other applications such as commercial refrigeration and consumer appliance applications.

It is known that edge seals in vacuum insulating panels have been made from either high temperature material (e.g., solder glass) with a high melting point, or from low temperature material with a low melting point. It is sometimes desirable to use low-temperature edge seal material (e.g., edge seal material having a low melting point) in a vacuum insulating panel so that the edge seal material can be heated to a lesser extent during manufacturing when forming the edge seal, so as to reduce de-tempering of glass substrates.

However, it has unfortunately been found that vacuum insulating panels having edge seals comprising low temperature material (at least one edge seal layer having a low melting point) outgas carbon monoxide, carbon dioxide, oxygen, and/or hydrogen rather quickly upon exposure to ultraviolet (UV) radiation. For example, seals tend to outgas carbon monoxide, carbon dioxide, oxygen, and/or hydrogen when exposed to high levels of UV radiation or prolonged exposure to ambient UV radiation, and vacuum getters contained internal to the vacuum cavity cannot adsorb all outgassed species emitted over a period of time from the low temperature seal material as a result of UV exposure. Thus, the vacuum insulating panel u-factors increase in an undesirable manner upon exposure to UV due to vacuum cavity contamination which increases the effective pressure in the cavity. The increase in u-factor reduces the useful life of the vacuum insulated panel making it challenging to achieve a desirable, e.g., twenty to thirty year product life.

The instant inventors have found a solution to this problem. The instant inventors have found that a cause of such UV induced degradation of vacuum insulating panels is high amounts of residual carbon remaining in low-temperature edge seal material after formation of the seal. Residual carbon is present in the edge seal material due to its presence in organic solvent(s) and binders such as polyalkylene carbonate, polypropylene (PP) carbonate, ethyl cellulose, methyl cellulose, or hydroxypropyl methyl cellulose used in the initial application of the edge seal material in the form of a paste. Such carbon containing solvent(s) and/or binder(s) are used in all ceramic edge seals for vacuum insulating panels as far as the instant inventors are aware. It has been found that high amounts of residual carbon remaining in the ceramic edge seal, after formation of the seal, leads to rather quick outgassing problems and increasing u-factors of the panel upon significant or prolonged UV exposure. In other words, the instant inventors have found that too much residual carbon remaining in the ceramic edge seal material of the final panel is problematic in these respects, especially upon UV exposure.

In certain example embodiments, processing has been improved in order to remove more carbon from low temperature edge seal material, so that less residual carbon remains in the ceramic edge seal of the final manufactured vacuum insulating panel. De-tempering of glass can be reduced by using low temperature edge seal material having a low melting point (possibly in combination with high temperature material for other seal layer(s) such as primer(s)), and by reducing residual carbon content in such low temperature edge seal material the manufactured panel is less susceptible to degradation upon UV exposure, and may in certain example embodiments be capable of one or more of approximately a twenty, twenty-five, and/or a thirty year product lifetime.

In certain example embodiments, there may be provided a vacuum insulating panel includes may include: a first substrate; a second substrate; a plurality of spacers provided in a gap between at least the first and second substrates, wherein the gap is at a pressure less than atmospheric pressure; a seal provided between at least the first and second substrates, the seal comprising a first seal layer, and optionally second and/or third seal layer(s). The first seal layer may be a low-temperature seal layer which has a low melting point to reduce de-tempering of glass substrate(s) during panel manufacturing. For example, the first seal layer may include tellurium oxide and/or vanadium oxide. The first seal layer may be processed in manner to reduce carbon content thereof so as to improve stability of the panel upon UV exposure.

In certain example embodiments, there may be provided a vacuum insulating panel comprising: a first substrate; a second substrate; a plurality of spacers provided in a gap between at least the first and second substrates, wherein the gap is at pressure less than atmospheric pressure; a seal provided at least partially between at least the first and second substrates, the seal comprising a ceramic first seal layer; and wherein the first seal layer has a melting point of no greater than about 450 degrees C. (more preferably no greater than about 430 degrees C., more preferably no greater than about 420 degrees C., for example no more than about 400 degrees C.) and comprises from about 5 to 70 ppm carbon (more preferably from about 5 to 43 ppm carbon).

In certain example embodiments, there may be provided a vacuum insulating panel comprising: a first glass substrate; a second glass substrate; a plurality of spacers provided in a gap between at least the first and second substrates, wherein the gap is at pressure less than atmospheric pressure; a seal provided at least partially between at least the first and second substrates, the seal comprising a first seal layer; wherein the first seal layer comprises tellurium oxide and/or vanadium oxide, and wherein on an elemental basis in terms of wt. % either Te or V has the largest content of any metal in the first seal layer; and wherein the first seal layer comprises from about 5 to 70 ppm carbon, more preferably from about 5-50 ppm carbon, more preferably from about 5 to 43 ppm carbon.

In certain example embodiments, there may be provided a vacuum insulating panel comprising: a first glass substrate; a second glass substrate; a plurality of spacers provided in a gap between at least the first and second substrates, wherein the gap is at pressure less than atmospheric pressure; a seal provided at least partially between at least the first and second substrates, the seal comprising a first seal layer; wherein the first seal layer comprises tellurium oxide and/or vanadium oxide, and wherein on an elemental basis in terms of wt. % either Te or V has the largest content of any metal in the first seal layer; and wherein the first seal layer comprises no more than about 70 ppm carbon, more preferably no more than about 50 ppm carbon, more preferably no more than about 45 ppm carbon, more preferably no more than about 40 ppm carbon, more preferably no more than about 35 ppm carbon, and most preferably no more than about 30 ppm carbon.

In certain example embodiments, there may be provided a vacuum insulating panel comprising: a first glass substrate; a second glass substrate; a plurality of spacers provided in a gap between at least the first and second substrates, wherein the gap is at pressure less than atmospheric pressure; a seal provided at least partially between at least the first and second substrates, the seal comprising a first seal layer and a second seal layer contacting each other; wherein the first seal layer comprises tellurium oxide and/or vanadium oxide; wherein the second seal layer comprises bismuth oxide and/or boron oxide, and wherein the second seal layer has a melting point at least 100 degrees higher than does the first seal layer; and wherein the first seal layer comprises no more than about 50 ppm carbon, and wherein the first seal layer on a ppm basis contains more carbon than does the second seal layer.

These features are technically advantageous, for example, providing for one or more of the following advantages: reduced de-tempering of glass substrate(s), higher seal density which improves the seal, improved seal hermiticity, improved seal moisture resistance, reduced panel degradation upon exposure to UV, increased panel lifetime, improved retention of panel u-factors upon exposure to UV, and/or improved seal durability.

The following detailed structural and/or functional description(s) is/are provided as examples only, and various alterations and modifications may be made. The example embodiments herein do not limit the disclosure and should be understood to include all changes, equivalents, and replacements within ideas and the technical scope herein. Hereinafter, certain examples will be described in detail with reference to the accompanying drawings. When describing various example embodiments with reference to the accompanying drawings, like reference numerals may refer to like components and a repeated description related thereto may be omitted.

are side cross sectional views each illustrating a vacuum insulating panelaccording to various example embodiments,is a side cross sectional view of an example vacuum insulating unit/panelshowing a laser used in sintering/firing the main seal layerwhen forming the edge sealduring manufacturing (which may be used in combination with any embodiment herein, andis a schematic top view of an example vacuum insulating unit/panelshowing a laser used in sintering/firing the main seal layerwhen forming the edge sealduring manufacturing (which may be used in combination with any embodiment herein). It should be noted that, in practice, such vacuum insulating panels/units may be oriented upside down or sideways from the orientations illustrated in. Vacuum insulating panelmay be used in window applications (e.g., for commercial and/or residential windows), and/or for other applications such as commercial refrigeration and consumer appliance applications.

Referring to, each vacuum insulating panelmay include a first substrate(e.g., glass substrate), a second substrate(e.g., glass substrate), a hermetic edge sealat least partially provided proximate the edge of the panel, and a plurality (e.g., an array) of spacersprovided between at least the substratesandfor spacing the substrates from each other and so as to help provide low-pressure space/gapbetween at least the substrates. Each glass substrate,may be flat, or substantially flat, in certain example embodiments. Support spacers, sometimes referred to as pillars, may be of any suitable shape (e.g., round, oval, disc-shaped, square, rectangular, rod-shaped, etc.) and may be of or include any suitable material such as stainless steel, aluminum, ceramic, solder glass, metal, and/or glass. Certain example support spacersshown in the figures are substantially circular as viewed from above and substantially rectangular as viewed in cross section, and may have rounded edges. The hermetic edge sealmay include one or more of main seal layer, upper primer layer, and lower primer layer. Each “layer” herein may comprise one or more layers. At least one thermal control and/or solar control coating, such as a multi-layer low-emittance (low-E) coating, may be provided on at least one of the substratesandin order to further improve insulating properties of the panel. The solar control coatingmay be provided on substrateor substrate, or such a solar control coating may be provided on both substratesand. For example,illustrate such a coating(e.g., low-E coating) provided on substrate, whereasillustrate the coatingprovided on substrate. Each substrateandis preferably of or including glass, but may instead be of other material such as plastic or quartz. For example, one or both glass substratesandmay be soda-lime-silica based glass substrates, borosilicate glass substrates, lithia aluminosilicate glass substrates, or the like, and may be clear or otherwise tinted/colored such as green, grey, bronze, or blue tinted. Substratesand, in certain example embodiments, may each have a visible transmission of at least about 40%, more preferably of at least about 50%, and most preferably of from about 60-80%. The vacuum insulating panel, in certain example embodiments, may have a visible transmission of at least 40%, more preferably of at least 50%, and most preferably of at least 60%. The substratesandmay be substantially parallel (parallel plus/minus ten degrees, more preferably plus/minus five degrees) to each other in certain example embodiments. Substratesandmay or may not have the same thickness, and may or may not be of the same size and/or same material, in various example embodiments. When glass is used for substratesand, each of the glass substrates may be from about 2-12 mm thick, more preferably from about 3-8 mm thick, and most preferably from about 4-6 mm thick. When glass is used for substratesand, the glass may or may not be tempered (e.g., thermally tempered). Although thermally tempered glass substrates are desirable in certain environments, the glass substrate(s) may be heat strengthened. As known in the art, thermal tempering of glass typically involves heating the glass to a temperature of at least 585 degrees C., more preferably to at least 600 degrees C., more preferably to at least 620 degrees C. (e.g., to a temperature of from about 620-650 degrees C.), and then rapidly cooling the heated glass so as to compress surface regions of the glass to make it stronger. The glass substrates may be thermally tempered to increase compressive surface stress and to impart safety glass properties including small fragmentation upon breakage. When tempered glass substratesand/orare used, the substrate(s) may be tempered (e.g., thermally or chemically tempered) prior to firing/sintering of main edge seal material(e.g., via laser) to form the edge seal.

When heat strengthened glass substratesand/orare used, the substrate(s) may be heat strengthened prior to firing/sintering of the main edge seal material(e.g., via laser) to form the edge seal. When a vacuum insulated glass panel/unit has one tempered glass substrate and one heat strengthened substrate, the substrate(s) may be tempered (e.g., thermally or chemically tempered) and heat strengthened prior to firing/sintering of the main edge seal material(e.g., via laser) to form the edge seal.

In various example embodiments, each vacuum insulating panel, still referring to, optionally may also include at least one sorption getter(e.g., at least one thin film getter) for helping to maintain the vacuum in low pressure spaceby using reactive material for soaking up and/or bonding to gas molecules that remain in space, thus providing for sorption of gas molecules in low pressure space. The gettermay be provided directly on either glass substrateor, or may be provided on a low-E coatingin certain example embodiments. In certain example embodiments, the gettermay be laser-activated and/or activated using inductive heating techniques, and/or may be positioned in a trough/recessthat may be formed in the supporting substrate (e.g., substrate) via laser etching, laser ablating, and/or mechanical drilling.

A vacuum insulating panelmay also include a pump-out tubeused for evacuating the spaceto a pressure(s) less than atmospheric pressure, where the elongated pump-out tubemay be closed/sealed after evacuation of the space. Pump-out sealmay be provided around tube, and a capmay be provided over the top of the tubeafter it is sealed. Tubemay extend part way through the substrate, for example part way through a double countersink hole drilled in the substrate as shown in. However, tubemay extend all the way through the substratein alternative example embodiments. Pump-out tubemay be of any suitable material, such as glass, metal, ceramic, or the like. In certain example embodiments, the pump-out tubemay be located on the side of the vacuum insulating panelconfigured to face the interior of the building when the panel is used in a commercial and/or residential window. In certain example embodiments, the pump-out tubemay instead be located on the side of the vacuum insulating panelconfigured to face the exterior of the building. The pump-out tubemay be provided in an aperture defined in either substrateorin various example embodiments. Pump-out sealmay be of any suitable material. In certain example embodiments, the pump-out sealmay be provided in the form of a substantially donut-shaped pre-form which may be positioned in a recessformed in a surface of the substrateor, so as to surround an upper portion of the tube, so that the pre-form can be laser treated/fired/sintered (e.g., after formation of the edge seal) to provide a seal around the pump-out tube. Alternatively, the pump-out sealmay be of any suitable material and/or may be dispensed in paste and/or liquid form to surround at least part of the tubeand may be sealed before and/or after evacuation of space. The pump-out seal materialmay be directly applied to the glass substrate material or to a primer layer applied to the glass substrate surface prior to the pump-out seal material being applied to the substrate, in certain example embodiments. After evacuation of space, the tip of the tubemay be melted via laser to seal same, and hermetic sealing of the spacein the panelcan be provided both by the edge sealand by the sealed upper portion of the pump-out tubetogether with sealand/or cap. In certain example embodiments, as shown infor example, the elongated pump-out tubemay be substantially perpendicular (perpendicular plus/minus ten degrees, more preferably plus/minus five degrees) to the substratesand. Any of the elements/components shown inmay be omitted in various example embodiments.

The evacuated gap/spacebetween the substratesand, in the vacuum insulating panel, is at a pressure less than atmospheric pressure. For example, after the edge sealhas been formed, the cavityevacuated to a pressure less than atmospheric pressure, and the pump-out tubeclosed/sealed, the gapbetween at least the substratesandmay be at a pressure no greater than about 1.0×10Torr, more preferably no greater than about 1.0×10Torr, more preferably no greater than about 1.0×10Torr, and for example may be evacuated to a pressure no greater than about 1.0×10Torr. The gapmay be at least partially filled with an inert gas in various example embodiments. In certain example embodiments, the evacuated vacuum gap/spacemay have a thickness (in a direction perpendicular to planes of the substratesand) of from about 100-1,000 μm, more preferably from about 200-500 μm, and most preferably from about 230-350 μm. Providing a vacuum in the gap/spaceis advantageous as it reduces conduction and convection heat transport, so as to reduce temperature fluctuations inside buildings and the like, thereby reducing energy costs and needs to heat and/or cool buildings. Thus, panelscan provide high levels of thermal insulation.

Example low-emittance (low-E) coatingswhich may be used in the vacuum insulating panelare described in U.S. Pat. Nos. 5,935,702, 6,042,934, 6,322,881, 7,314,668, 7,342,716, 7,632,571, 7,858,193, 7,910,229, 8,951,617, 9,215,760, and 10,759,693, the disclosures of which are all hereby incorporated herein by reference in their entireties. Other low-E coatings may also, or instead, be used. A low-E coatingtypically includes at least one IR reflecting layer (e.g., of or including silver, gold, or the like) sandwiched between at least first and second dielectric layer(s) of or including materials such as silicon nitride, zinc oxide, zinc stannate, and/or the like. A low-E coatingmay have one or more of: (i) a hemispherical emissivity/emittance of no greater than about 0.20, more preferably no greater than about 0.04, more preferably no greater than about 0.028, and most preferably no greater than about 0.015, and/or (ii) a sheet resistance (R) of no greater than about 15 ohms/square, more preferably no greater than about 2 ohms/square, and most preferably no greater than about 0.7 ohms/square, so as to provide for solar control. In certain example embodiments, the low-E coatingmay be provided on the interior surface of the glass substrate to be closest to the building exterior, which is considered surface two (e.g., see), whereas in other example embodiments the low-E coatingmay be provided on the interior surface of the glass substrate to be closest to the building interior, which is considered surface three (e.g., see).

illustrates an embodiment where the edge sealis provided in the vacuum insulated glass panelat the absolute edge, the seal layers,andall have substantially the same width (e.g., between about 6 mm and 12 mm), and a thickness of the main seal layeris less than a thickness of primer layerbut greater than a thickness of the other primer layer.illustrates an embodiment where the edge sealis spaced inwardly from the absolute edge of the panel, the width of the main seal layeris less than a width(s) of the primer layersand, and a thickness of the main seal layeris greater than a thickness of primer layerbut less than a thickness of the other primer layer.illustrates an embodiment where the edge sealis spaced inwardly from the absolute edge of the panel, the seal layers,andall have substantially the same width (e.g., between about 6 mm and 12 mm), and the seal layers,andall have substantially the same thickness.illustrates an embodiment where the edge sealis spaced inwardly from the absolute edge of the panel, the width of the main seal layeris less than a width(s) of the primer layersand, a thickness of the main seal layeris greater than a thickness of primer layerbut less than a thickness of primer layer, and the low-E coatingis provided on substrate(as opposed to the low-E coating being on substratein).illustrates an embodiment similar to, except that primer layeris omitted in theembodiment.provides an example where a laser beamfrom laseris being used to heat the edge seal structure for sintering/firing the main seal layerto form the hermetic edge seal, andis a top view illustrating the laser beamproceeding around the entire periphery of the panel along pathover the edge seal layers-to fire/sinter the main edge seal layerin forming the hermetic edge seal. The laser beamperforms localized heating of the edge seal area, so as to not unduly heat certain other areas of the panel thereby reducing chances of significant de-tempering of the glass substrates. Each of these embodiments may be used in combination with any other embodiment described herein, in whole or in part.

Edge seal, which may include one or more of ceramic layers-, may be located proximate the periphery or edge of the vacuum insulated panelas shown in. Edge sealmay be a ceramic edge seal in certain example embodiments. Referring to, in certain example embodiments, layerof the edge seal may be considered a main or primary seal layer, and layersandmay be considered primer layers. One or more of seal layers-, of the edge seal, may be of or include ceramic frit in certain example embodiments, and/or may be lead-free or substantially lead-free (e.g., no more than about 15 ppm Pb, more preferably no more than about 5 ppm Pb, even more preferably no more than about 2 ppm Pb) in certain example embodiments. In certain example embodiments, each primer layerandmay be of a material having a coefficient of thermal expansion (CTE) that is between that of the main seal layerand the closest glass substrate,. For example, referring to, primer layersandmay each have a CTE (e.g., from about 8.0 to 8.8×10mm/(mm*deg. C.), more preferably from about 8.3 to 8.6×10mm/(mm*deg. C.)) which is between a CTE (e.g., from about 8.7 to 9.3×10mm/(mm*deg. C.), more preferably from about 8.8 to 9.2×10mm/(mm*deg. C.)) of the adjacent float glass substrateand a CTE (e.g., from about 7.0 to 7.9×10mm/(mm*deg. C.), more preferably from about 7.2 to 7.9×10mm/(mm*deg. C.), with an example being about 7.6×10mm/(mm*deg. C.)) of the main seal layer. The main seal layermay have a CTE of at least 15% less than CTE(s) of the glass substrate(s)and/orin certain example embodiments. Thus, the multi-layer edge seal, via primer(s)and/or, may provide for a graded CTE from the main sealmoving toward each glass substrate,, which provides for improved bonding of the edge seal to the glass and a more durable resulting vacuum insulating panelsuch as capable of surviving exposure to asymmetric thermal loading and/or wind loads in the end application. The main seal layer, in certain example embodiments, need not contain significant amounts of CTE filler material (although it may contain significant amounts of filler in other example embodiments), which can result in an improved hermetic edge sealand durability. A primer(s)and/ormay be omitted in certain example embodiments. In certain example embodiments, primer layersandmay be of or include different material(s) compared to the main seal layer.

In certain example embodiments, in the edge seal, edge seal layermay be of or include a low temperature material having a relatively low melting point (Tm), and one or both of seal layersand/ormay be of or include a high temperature material having a relatively high melting point (Tm). Thus, in certain example embodiments, at least one of the edge seallayers may have a low melting point (e.g., layer). In certain example embodiments, one or both primer layersand/orof the edge seal may have a high melting point (Tm) of at least about 500 degrees C., more preferably of at least about 600 degrees, C, whereas the main seal layermay have a melting point (Tm) of no greater than about 450 degrees C., more preferably no greater than about 430 degrees C., more preferably no greater than about 420 degrees C., and most preferably no greater than about 410 degrees C.

In certain example embodiments, before and/or after sintering/firing, one or both primer layer(s)and/ormay have a melting point (Tm) higher than the melting point of the main seal layer. For example, in certain example embodiments, one or both primer layersand/ormay have a melting point (Tm) of from about 500-750 degrees C. (more preferably from about 575-680 degrees C., and most preferably from about 600-650 degrees C.), whereas the main seal layermay have a lower melting point (Tm) of from about 300 to 450 degrees C. (more preferably from about 350-430 degrees C., and most preferably from about 380-420 degrees C. or from about 390-410 degrees C.). In certain example embodiments, one or both of the primer layersand/ormay have a melting point (Tm) at least 100 degrees C. higher, more preferably at least 150 degrees C. higher, and most preferably at least 200 degrees C. higher, than the melting point of the main seal material. For purposes of example, in an example embodiment the main seal layermay have a melting point of from about 390-410 degrees C. or from about 390-395 degrees C., whereas the primer layersandmay each have a melting point of from about 585-625 degrees C. or from about 610-625 degrees C. In certain example embodiments, before and/or after sintering/firing, one or both primer layer(s)and/ormay have a transition point (Tg) higher than the transition point of the main seal layer. For example, in certain example embodiments, before and/or after sintering/firing, one or both primer layer(s)and/ormay have a transition point of from about 400-600 degrees C. (more preferably from about 425-550 degrees C., and most preferably from about 450 to 510 degrees C.), whereas the main seal layermay have a lower transition point of from about 200 to 350 degrees C. (more preferably from about 230-330 degrees C., and most preferably from about 260 to 310 degrees C.). In a similar manner, in certain example embodiments, before and/or after sintering/firing, one or both primer layer(s)and/ormay have a softening point (Ts) higher than the softening point of the main seal layer. For example, in certain example embodiments, one or both primer layer(s)and/ormay have a softening point of from about 425-650 degrees C. (more preferably from about 475-620 degrees C., and most preferably from about 520 to 590 degrees C.), whereas the main seal layermay have a lower softening point of from about 220 to 410 degrees C. (more preferably from about 270-380 degrees C., and most preferably from about 300 to 340 degrees C.). In certain example embodiments, before and/or after sintering/firing, one or both of the primer layer(s)and/ormay have a softening point (Ts) at least 100 degrees C. higher, more preferably at least about 150 degrees C. higher, and most preferably at least about 150 or 200 degrees C. higher, than the softening point (Ts) of the main seal layer material. For purposes of example, in an example embodiment the main seal layermay have a softening point of from about 310-330 degrees C., whereas the primer layersandmay each have a softening point of from about 540-560 degrees C. For purposes of example, in an example embodiment the main seal layermay have a melting point of from about 390-395 degrees C., whereas the primer layersandmay each have a melting point of from about 610-625 degrees C. These feature(s) advantageously may allow each high melting point primer layersandto provide strong mechanical bonding with the supporting glass substrate (and/or) via sintering/firing in a first bulk heating step in an oven or other heater (e.g., heating above the melting point and/or softening point of the primer(s) while thermally tempering the glass substrate,on which the primer is provided), and thereafter sintering/firing the lower melting point main seal materialin a different second heating step (e.g., via laser) to bond the main seal layerto the previously sintered/fired primersandand form the edge sealwithout significantly de-tempering the glass substrates. Thus, the main seal layerand primersandcan be sintered/fired in different heating steps, in a manner which allows thermal tempering of the glass substratesandwhen sintering/heating the primers on the respective glass substrates, and which allows the main seal layerto thereafter be sintered and bonded to the primersandwithout significantly de-tempering the glass substratesand. This advantageously results in more efficient processing, reduction in damage, and a more durable and longer lasting vacuum insulating panel with much of its temper strength retained allowing for example compliance with industry safety testing for bag impact and/or point impact fragmentation.

The edge seal, in certain example embodiments, may be located at an edge-deleted area (where the solar control coatinghas been removed) of the substrate as shown in. Thus, the edge sealmay be positioned so that it does not overlap the low-E coatingin certain example embodiments. The edge sealmay be located at the absolute edge of the panel(e.g.,), or may be spaced inwardly from the absolute edge of the panelas shown in, in different example embodiments. An outer edge of the hermetic edge sealmay be located within about 50 mm, more preferably within about 25 mm, and more preferably within about 15 mm, of an outer edge of at least one of the substratesand/or. Thus, an “edge” seal does not necessarily mean that the edge sealis located at the absolute edge or absolute periphery of a substrate(s) or overall panel.

The low-E coatingmay be edge deleted around the periphery of the entire unit so as to remove the low-e coating material from the coated glass substrate. The low-E coatingedge deletion width (edge of glass to edge of low-E coating), in certain example embodiments, in at least one area may be from about 0-100 mm, with examples being no greater than about 6 mm, no greater than about 10 mm, no greater than about 13 mm, no greater than about 25 mm, with an example being about 16 mm. In certain example embodiments, there may be a gap between the primer seal layersandand/or main layer, and the low-E coating, of at least about 0.5 mm, more preferably a gap of at least about 1.0 mm, and for example a gap of at least about 5 mm so that the low-E coatingis not contiguous with the main seal layerand/or the primer seal layersand.

It has been found that adjusting the width (as viewed from above and/or in cross-section) of the main seal layer, of the edge seal, can be technically advantageous. It has been found that when the main seal layeris too wide, this results in undesirably high induced transient thermal stress in the main seal layerwhich can lead to seal issues and/or a non-durable product. Reduced width of the main seal layercan also improve U-value/U-factor performance of panel., for example, illustrate that the main edge seal layermay have a width less than the width of one or both of the adjacent primer layersand. For example, see the width “W” of the main seal layerin. In an example embodiment, the width of the main seal layermay be about 6 mm. Moreover, if the primer layer(s)and/oris/are made too narrow, this can reduce the bonding area resulting in edge seal issues., for example, illustrate that the main edge seal layerhas a width “W” less than the width (e.g., “Wp”) of the adjacent primer layersand. In an example embodiment, the width of the main seal layermay be about 6 mm and the width of the primer layersandmay be about 10 mm, so that the width of one or both of the primer layers is greater than the width of the main seal layer (e.g., see). In certain example embodiments, the width of the ceramic sealing glass primer layermay be about 8 mm, the width of the ceramic sealing glass primer layermay be about 8 mm, and the width of the ceramic main seal layermay be about 6 mm or about 3-4 mm. Thus, in certain example embodiments and referring tofor example, in the manufactured vacuum insulating panel, the main seal layerof the edge sealmay have an average width W of from about 2-20 mm, more preferably from about 4-10 mm, more preferably from about 3-9 mm or from about 4-8 mm, still more preferably from about 5-7 mm, and with an example main seal layeraverage width being about 6 mm; and/or one or both of the primer layersandmay have an average width Wp of from about 2-20 mm, more preferably from about 6-14 mm, more preferably from about 8-12 mm, still more preferably from about 9-11 mm, and with an example primer average width being about 10 mm. In certain example embodiments, the respective width(s) of each layer,, andmay be substantially the same (the same plus/minus 10%, more preferably plus/minus 5%) along the length of the edge sealaround the periphery of the entire panel. In certain example embodiments, the ratio Wp/W of the width Wp of one or both primer layers,to the width W of the main seal layermay be from about 1.2 to 2.2, more preferably from about 1.4 to 1.9, and most preferably from about 1.5 to 1.8 (e.g., the ratio Wp/W is 1.67 when a primer layerand/oris 10 mm wide and the main seal layeris 6 mm wide: 10/6=1.67). In certain example embodiments, one or both primer layersand/oris/are at least about 1 mm wider, more preferably at least about 2 mm wider, and most preferably at least about 3 mm wider, than the main seal layerat one or more locations around the periphery of the paneland possibly around the entire periphery of the panel. These desirable widths for ceramic seal layers-in the panelmay be appropriate when using the materials for seal layers-discussed herein (e.g., see), and may be adjusted in an appropriate manner if different seal materials are instead used which is possible in certain example embodiments. Other widths for one or more of seal layers-, not discussed herein, may be used in various other example embodiments. In certain example embodiments, as viewed from above and/or in cross-section as shown infor example, the lateral edge(s)and/orof the main seal layermay be spaced inwardly an offset distance “D” from the respective lateral edges of the primer seal layerand/or the primer seal layeron each side of the main seal layer. In certain example embodiments, the offset distance “D” on one or both sides of the main seal layermay be from about 0.5 to 6.0 mm, more preferably from about 0.5 to 3.0 mm, more preferably from about 0.5 to 2.5 mm, more preferably from about 1.0 to 2.5 mm, and most preferably from about 1.5 to 2.5 mm, with an example being about 2.0 mm on each side, although the offset distance “D” may be different on the left and right sides of the main seal layer as viewed infor example. In certain example embodiments, the offset distance “D” on one or both sides of the main seal layermay be at least about 0.5 mm, more preferably at least about 1.0 mm, and most preferably at least about 1.5 mm, as shown infor example. See also. In certain example embodiments and referring tofor example, in the manufactured vacuum insulating panel, the main seal layerof the edge sealmay have an average thickness of from about 30-120 μm, more preferably from about 40-100 μm, and most preferably from about 50-85 μm, with an example main seal layeraverage thickness being from about 60-80 μm as shown in. In certain example embodiments, in the manufactured vacuum insulating panel, the primer layerof the edge sealmay have an average thickness of from about 10-80 μm, more preferably from about 20-70 μm, and most preferably from about 20-55 μm, with an example primer layeraverage thickness being about 45 μm as shown in. In certain example embodiments, in the manufactured vacuum insulating panel, the primer layer(opposite the side from which the laser beamis directed) of the edge sealmay have an average thickness of from about 100-220 μm, more preferably from about 120-200 μm, and most preferably from about 120-170 μm, with an example primer layeraverage thickness being about 145 μm as shown in. In certain example embodiments, the thickness of the main seal layermay be at least about 30 μm thinner (more preferably at least about 45 μm thinner) than the thickness of the primer seal layer, and may be at least about 10 μm thicker (more preferably at least about 20 μm, and more preferably at least about 30 μm thicker) than the thickness of the primer seal layer. In certain example embodiments, in the manufactured vacuum insulating panel, the overall average thickness of the edge sealmay be from about 150-330 μm, more preferably from about 200-310 μm, and most preferably from about 240-290 μm, with an example overall edge sealaverage thickness being about 270 μm as shown in. In certain example embodiments, the respective thicknesses of each layer,, andare substantially the same (the same plus/minus 10%, more preferably plus/minus 5%) along the length of the edge sealaround the periphery of the entire panel. Further details of the edge seal structure, dimensions of the edge seal and other components, characteristics of the edge seal and other components, materials, and the manufacture of the overall panel may be provided in one or more of U.S. patent application Ser. Nos. 18/376,914, 18/376,473, 18/376,479, 18/376,483, 18/379,275, and 18/510,777, the disclosures of which are all hereby incorporated herein by reference in their entireties.

In various example embodiments, lasermay be selected to emit a laser beamhaving a wavelength (λ) of from about 550 nm to 1064 nm, more preferably from about 780-1064 nm. Lasermay be a near IR laser in certain example embodiments. Lasermay be a continuous wave laser, a pulsed laser, and/or other suitable laser in various example embodiments. In various example embodiments, the lasermay be a scanning laser system comprising diode, ND:YAG, COand/or other laser devices/sources. In certain example embodiments, lasermay emit a laser beamat or having a wavelength of about 800 nm, 808 nm, 810 nm, 940 nm, or 1090 nm (e.g., YVO4 laser). In certain example embodiments, more than one laser may be utilized to increase the sealing speed, lower effective laser power levels and/or reduce laser spot size. Two lasers operating in a serial, overlapping manner can increase the effective irradiation spot time to achieve for example 0.5 seconds while achieving for example a 20 mm per second linear laser rate, as an example. Two 9-mm laser diameter beams, for example, can operate in a serial fashion for a 0.5 second to 1.0 second irradiation time.

illustrate an example material(s) that may be used for the main seal layerin various example embodiments, including for example in any of the embodiments of. However, other suitable materials (vanadium oxide based ceramic materials with little or no Te oxide, solder glass, or the like) may instead be used for layerin various example embodiments.is a table/graph showing weight % and mol % of various compounds/elements in an example main sealmaterial, prior to sintering of layer, according to an example embodiment (measured via non-carbon detecting XRF);is a table/graph showing weight % and mol % of various compounds/elements in an example main sealmaterial according to an example embodiment (measured via carbon detecting XRF), before and after laser treatment/sintering of the main seal layerfor edge seal formation; and the left side ofsets forth a table/graph showing an elemental analysis (non-oxide analysis) of weight % and mol % of various elements in an example main sealmaterial, before and after laser treatment for edge seal formation. Regarding, X-ray Fluorescence (XRF) is a non-destructive technique that can identify and quantify the elemental constituents of a sample using the secondary fluorescence signal produced by irradiation with high energy x-rays, and wavelength dispersive spectrometer (WDXRF) is capable of detecting elements from atomic number (Z)(beryllium) through atomic number(uranium) at concentrations from the low parts per million (ppm) range up to 100% by weight.

This ceramic tellurium (Te) oxide based main seal material, shown in, was used for main seal layerin examples tested for obtaining data herein for various figures/tables unless otherwise specified. This ceramic tellurium (Te) oxide based main seal material, shown in, for example may be considered to have a melting point (Tm) of 390 or 395 degrees C., a softening point (Ts) of 320 degrees C., and a glass transition point (Tg) of 290 degrees C.

Table 1A sets forth example ranges for various elements and/or compounds for this example tellurium (Te) oxide based main sealmaterial according to various example embodiments, for both mol % and weight %, prior to firing/sintering thereof and thus prior to hermetic edge sealformation. The carbon (C) content in Table 1A was measured between stepsandin, namely after the material for seal layerwas applied in paste form including organic solvent and binder and after the paste was dried to substantially remove the solvent and heated to remove significant amounts of residual carbon—but prior to pre-glaze heating in stepand prior to laser sintering in step. Unlike the other elements and/or compounds in Table 1A, the carbon content is in units of ppm. In certain example embodiments, the main seal layermay comprise mol % and/or wt. % of the following compounds in one or more of the following orders of magnitude: tellurium oxide>vanadium oxide>aluminum oxide, tellurium oxide>vanadium oxide>silicon oxide, tellurium oxide>vanadium oxide>aluminum oxide>magnesium oxide, and/or tellurium oxide>vanadium oxide>silicon oxide>magnesium oxide, before and/or after firing/sintering of the layer. It will be appreciated that other materials may be used together, or in place of, those shown below, and that the example percentages may be different in alternate embodiments.

Tellurium Vanadate based and/or inclusive glasses (including tellurium oxide and/or vanadium oxide), such as those in Table 1A, in certain example embodiments are ideally suited for the main seal layerfunctionality when utilizing laser irradiation for the firing/sintering of the main seal layer. The base main seal material may comprise tellurium oxide (e.g., a combination of TeO, TeO, and TeO) and vanadium oxide (e.g., a combination of VO, VO, and VO) per the weight % and/or mol % described in Table 1A. In certain example embodiments, it may be desirable to have a higher amount of tellurium oxide compared to vanadium oxide, in order to increase the material density in the sintered state and thus improve hermiticity of the seal. Other low-temperature materials, with relatively low melting point, may instead and/or also be used for seal layer. With respect to example main seal material(s) in Table 1A for the main seal layer, the Te oxide (e.g., one or more of TeO, TeO, TeO, and/or other stoichiometry(ies) involving Te and O) and V oxide (e.g., one or more of VO, VO, VO, and/or other stoichiometry(ies) involving V and O) in the material may be made up of about the following stoichiometries before/after sintering as shown below in Table 1B (tellurium oxide stoichiometries prior to firing/sintering), Table 1C (tellurium oxide stoichiometries after firing/sintering), Table 1D (vanadium oxide stoichiometries prior to firing/sintering), Table 1E (vanadium oxide stoichiometries after firing/sintering), respectively, measured via XPS.

For example, the “Example” column in Table 1B indicates that 57% of the Te present in the material prior to sintering/firing was in an oxidation state of TeO, 42% of the Te present in the material prior to sintering/firing was in an oxidation state of TeO, and 1% of the Te present in the material prior to sintering/firing was in an oxidation state of TeO. And the “Example” column in Table 1C indicates that after the laser firing/sintering of the main seal layerjust 14% of the Te present in the main seal layermaterial was in an oxidation state of TeO, but 81% of the Te present in the material was in an oxidation state of TeO, and 5% of the Te present in the material prior to sintering/firing was in an oxidation state of TeO. Accordingly, in certain example embodiments, it will be appreciated that the laser firing/sintering of the main seal layermay cause much of the TeOto transform/convert into TeOand TeO, which is advantageous because it increases the material's absorption in the near infrared (e.g., 808 or 810 nm for example, which may be used for the laser during sintering/firing) which provides for increased heating efficiency and reducing the chances of significantly de-tempering the glass substrate(s) due to improved heating efficiency during the firing/sintering.

Regarding Tables 1B-1C, there may be a shift in binding energy for Te in the main seal layercaused by laser sintering/firing thereof according to an example embodiment. In certain example embodiments, laser sintering/firing may cause a distinct shift in binding energy associated with Te in main seal layer. A binding energy shift toward depolymerized tellurite structures. The laser sintering/firing of the main seal layermay also cause the binding energy peak for V to shift in a distinct manner, corresponding to a reduction of Vto V/Vin the main seal layer. For example, in certain example embodiments, the laser sintering/firing of the main seal layerin stepmay cause at least one of in the main seal layer: (a) a binding energy shift of the Te peak of at least about 0.15 eV, more preferably of at least about 0.20 eV, and most preferably of at least about 0.25 or 0.30 eV, which resulted in the stoichiometry changes discussed in Tables 1B-1C and the related advantages discussed above, and/or (b) a binding energy shift of the V peak of at least about 0.10 eV, more preferably of at least about 0.15 eV, which resulted in the stoichiometry changes discussed in Tables 1D-1E and the related advantages discussed above. In contrast, in certain example embodiments, the laser sintering/firing of the preform sealfor the pump-out tube seal did not result in a distinct binding energy shift of the Te peak or the V peak for preform, demonstrating that not all laser sintering/firing techniques have such an effect.

In certain example embodiments, prior to firing/sintering, the material for the main seal layermay include tellurium oxide with the following stoichiometry/oxidation state ratio(s) in terms of what oxidation state(s) are used by the Te in the material (e.g., see Table 1B): TeO>TeO>TeO. But the laser sintering/firing of the main seal layer may then cause the Te stoichiometry ratios/states to change to the following during/after sintering/firing: TeO>TeO>TeO, which is advantageous in vacuum insulating panels as discussed above. The TeOis a trigonal bipyramid structure, TeOis a trigonal pyramid structure, and TeOis a polyhedral structure. In certain example embodiments, due to optimized laser treatment for firing/sintering of the main seal layer as discussed herein, the TeOlargely converts to TeOand marginally to TeOwith increasing temperature with a concurrent increase in the number of Te═O sites resulting from cleavage within the network structure. Tellurium oxide may have, for example, a Tg of about 305 degrees C., a crystallization temperature (Tx) of about 348 degrees C., and a Tm about 733 degrees C.

For example, the “Example” column in Table 1D indicates that 84% of the V present in the material prior to sintering/firing was in an oxidation state of VO, 15% of the V present in the material prior to sintering/firing was in an oxidation state of VO, and 1% of the V present in the material prior to sintering/firing was in an oxidation state of VO. And the “Example” column in Table 1E indicates that after the laser firing/sintering of the main seal layer just 25% of the V present in the main seal layermaterial was in an oxidation state of VO, but 63% of the V present in the material was in an oxidation state of VO, and 12% of the V present in the material prior to sintering/firing was in an oxidation state of VO. The other columns in Tables 1B-1E represent the same, with different values as shown. Accordingly, in certain example embodiments, it will be appreciated that the laser firing/sintering of the main seal layermay cause much of the VOto transform/convert into VOand VO, which is advantageous because it increases the material's density and thus the hermiticity and durability of the seal (e.g., VOresults in a more dense layer than does VO). In certain example embodiments, it is desirable to reduce the VOcontent in the final sintered/fired state of the main sealbecause the glass network becomes more closed with decreasing VOconcentration, e.g., due to the reduction of non-bridging oxygen resulting in a higher density seal which improves water/moisture resistance, mechanical strength (adhesive and cohesive), and/or hermeticity. The Tg of the main sealmaterial may also slightly increase with a reduction in VO.

In certain example embodiments, the vanadium oxide in the main seal layer material, before firing/sintering of the main seal layer, may include the following stoichiometry/oxidation state ratio(s): VO>VO>VO. But the laser sintering/firing of the main seal layermay then cause the V stoichiometry ratios/states to change to the following during/after sintering/firing: VO>VO>VO, which is advantageous in vacuum insulating panels as discussed at least because it allows for higher density in the final seal layer. The VOis an orthorhombic structure, VOis a tetragonal structure, and VOis corundum structured in the monoclinic C2/c space group. Vanadium is an insulator in a base form due to empty d-bands and acts as a network former/network modifier in the presence of tellurium oxide in the main seal material for layerand/or the pump-out tube seal in certain example embodiments. Vanadium oxide may have, for example, a Tg about 250 degrees C., a crystallization temperature (Tx) about 300 degrees C., and a Tm about 690 degrees C.

Thus, from Tables 1B-1E and, it will be appreciated that in certain example embodiments an optimized type of laser processing (e.g., 808 or 810 nm continuous wave laser using the process inand a laser beam size of about 6 mm, following a pre-heat to about 300-320 degrees C.) may be used to sinter/fire the main seal layerin a manner that causes one or more, or any combination, of the following to occur during and/or as a result of the sintering/firing: (a) stoichiometry values/oxidation states of Te in the layer to change from TeO>TeO>TeOprior to laser firing/sintering, to TeO>TeO>TeOfollowing laser firing/sintering of the layer; (b) stoichiometry values/oxidation states of Te in the layer to change from TeO>TeOprior to laser firing/sintering, to TeO>TeOfollowing laser firing/sintering of the layer; (c) stoichiometry values/oxidation states of vanadium (V) in the layer to change from VO>VO>VOprior to laser firing/sintering, to VO>VO>VOafter laser firing/sintering of the layer; (d) stoichiometry values/oxidation states of V in the layer to change from VO>VOprior to laser firing/sintering, to VO>VOafter laser firing/sintering of the layer; (e) the ratio TeO:TeOto change from about 1.0 to 2.0 (more preferably from about 1.2 to 1.6, more preferably from about 1.3 to 1.5) prior to sintering/firing to from about 0.05 to 0.40 (more preferably from about 0.10 to 0.30, more preferably from about 0.13 to 0.22) after the laser sintering/firing of the layer; (f) the ratio VO:VOto change from about 1.0 to 10.0 (more preferably from about 3.0 to 8.0, more preferably from about 4.5 to 7.0, with an example being 84:15=5.66) prior to sintering/firing to from about 0.10 to 0.90 (more preferably from about 0.20 to 0.80, more preferably from about 0.25 to 0.50, with an example being 25:63=0.39) after the laser sintering/firing of the layer; (g) a binding energy shift of the Te peak of at least about 0.15 eV, more preferably of at least about 0.20 eV, and most preferably of at least about 0.25 or 0.30 eV; and/or (h) a binding energy shift of the V peak of at least about 0.10 eV, more preferably of at least about 0.15 eV.

This main seal material(s) from Table 1 and, or substantially the same material, may also be used for the pump-out tube seal, with or without a primer, in certain example embodiments, although other types of seals may also be used such as vanadium oxide based ceramic sealing glass or solder glass. Other compounds may also be provided in this main sealmaterial, including but not limited to, on a weight and/or mol basis, for example one or more of: 0-15% (more preferably 1-10%) tungsten oxide; 0-15% (more preferably 1-10%) molybdenum oxide; 0-60% (or 38-52%) zinc oxide; 0-15% (more preferably 0-10%) copper oxide, and/or other elements shown in the figures.

Table 2 sets forth example ranges for various elements and/or compounds for this example tellurium oxide-based material for main seal layeraccording to various example embodiments, for both mol % and weight %, after firing/sintering thereof and thus after hermetic edge sealformation. The carbon (C) content in Table 2 was of course measured after step(s)and/orin, namely after at least pre-glaze heating in step. Unlike the other elements and/or compounds in Table 2, the carbon content is in units of ppm due to the small amounts involved. It will be appreciated that other materials may be used together, or in place of, those shown below, and that the example percentages may be different in alternate embodiments.

This material from Tables 1-2 andmay also be used for the pump-out tube seal, with or without a primer, in certain example embodiments, although other types of seals may also be used such as vanadium oxide based ceramic sealing glass or solder glass. Other compounds may also be provided in or for this main sealmaterial, including but not limited to, on a weight or mol basis, for example one or more of: 0-15% (more preferably 1-10%) tungsten oxide; 0-15% (more preferably 1-10%) molybdenum oxide; 0-60% (or 38-52%) zinc oxide; 0-15% (more preferably 0-10%) copper oxide, and/or other elements shown in the figures. Certain elements may change during firing/sintering, and certain elements may at least partially burn off during processing prior to formation of the final edges seal.

In certain example embodiments, particle size for the material of the main seal layermay be optimized for reduced particle size (e.g., for the D50 distribution) to improve material density and moisture resistance, and/or to improve thermal diffusivity. Traditional ceramic sealing glass materials have a D50 in the range of about 60.0 um to about 90.0 um which is acceptable for a thermal oven sintering process as an example, but has been found to experience some issues for laser processing. For laser processing, it has been found that improved results can be achieved by reducing particle size of the main seal layer. In certain example embodiments, the average D50 particle size and PSD mean may be significantly lower than traditional ceramic sealing glasses, as particle size is related to a thermal diffusivity rate of the ceramic sealing glass materials. Moreover, it has surprisingly been found that if the particle size is too large, then the density of the layertends to decrease and porosity tends to increase, and the layer becomes more susceptible to water and/or air leakage. It has also been found that too large of a particle size may contribute to significant de-tempering of the glass during edge seal formation, e.g., due to increasing lasing temperature and/or duration. Thus, small particle size may be used for layer(and one or more of layers-) in certain example embodiments. In certain example embodiments, before and/or after edge seal formation, the main seal layermay have an average particle/grain size (D50) of from about 5-25 μm, more preferably from about 5-20 μm, more preferably from about 5-15 μm, and most preferably from about 10-15 μm. These same particle sizes may also be used for one or both primer layersand/or, and/or tube seal material, before and/or after firing/sintering.

In certain example embodiments, the material for the main seal layermay include filler. The amount of filler may, for example, be from 1-25 wt. % and may have an average grain size (d50) of 5-30 μm, for example an average d50 grain size from about 5-20 μm, more preferably from about 5-15 μm, and most preferably less than about 10 μm. Mixtures of two or more grain size distributions (e.g., coarse: d50=15-25 μm and fine: d50=1-10 μm) may be used. The filler may, for example, comprise one or more of zirconyl phosphates, dizirconium diorthophosphates, zirconium tungstates, zirconium vanadates, aluminum phosphate, cordierite, eucryptite, ekanite, alkaline earth zirconium phosphates such as (Mg,Ca,Ba,Sr) ZrP0, either alone or in combination. Filler in a range of 20-25 wt. % may be used in layerin certain example embodiments. Seal layermay also include residual elements, such as carbon, from solvent(s) and binder (e.g., polypropylene carbonate is an example binder) that were present in the material as originally applied to the substrate in paste form. While polypropylene carbonate and/or poly(propylene carbonate) may be used as a binder in layers,and/orwhen initially applied in paste form, other binders may also and/or instead be used such as ethyl cellulose in various example embodiments. Main seal layer, and/or the primer layer(s)and/or, is/are lead-free and/or substantially lead-free in certain example embodiments.